Search

This study concerns the management of operational risk in truck transport using the reliability theory of risks. In this regard, the risk analysis of changes in the vehicle unavailability represents an important topic. In this study, the authors present their own method for analysing the phase changes in risk corresponding to successive sections (phases) of vehicle mileage. The presented risk analysis method is based on an integrated assessment of losses associated with the costs of incidental repairs and losses caused by lost income during vehicle downtime. This includes the following: assessment of differences in average risk and differences in the coefficient of variation in the time series of vehicle mileage phases, indicating the outliers and extremes of phase risk, identifying their physical causes and testing the statistical significance of phase risk differences. The proposed method is described mathematically and verified experimentally based on the operational data concerning trucks from two selected brands (20 trucks from each brand). We show that the method can be used to predict the continuity of transport services in the short term (one-year horizon). The method could also be useful to compare vehicles of different brands in the context of their sensitivity to operational risks. [ABSTRACT FROM AUTHOR]

A proposal was presented to assess the incapacity risk of commercial vehicles performing transport tasks under market conditions. The risk assessment model in the form of cost was used, which is based on the determination of operational efficiency, referring the probable costs of ensuring the reliability of the transport system to the estimated threshold income. It includes costs: incidental repairs, unplanned downtime and resulting from the presumed loss of client's trust. Operational research were carried out on a group of several dozen vehicles, registering their operational states during several years of use. The results of the research confirmed the suitability of the incapacity risk model for predicting potential expenses for guarantee the vehicle's continuity of running in the company and to verify the selection of the vehicle brand and the period of use. [ABSTRACT FROM AUTHOR]

The paper describes operational efficiency research of city buses from two manufacturers during the 6 years of operation under real conditions. The presented operational efficiency assessment model includes unplanned incidental repairs costs, downtime costs, as well as the likelihood of losing customer-passenger's trust. The results of the efficiency calculations were used to estimate the expected costs of buses' incapacity risk. It has been demonstrated that the operational efficiency and incapacity risk costs can be a criterion for the optimal period of operation, as well as the criterion of comparison of bus makes in a transport company. [ABSTRACT FROM AUTHOR]

When a trolleybus travels through insulated sections of the overhead contact line, it experiences momentary power interruptions, which adversely affect the vehicle's on-board auxiliary subassemblies. To reduce these negative effects, one can harness energy recovered via regenerative braking. A model power supply circuit diagram for structural systems of the trolleybus is proposed. Simulation tests were carried out to develop a method for analyzing power supply to trolleybus auxiliary devices and verify it in a real-life example. The results allow determination of the limit power that can be generated by the trolleybus drive system to feed auxiliary devices during interruptions in power supply from the overhead contact line. The possibility of powering the on-board auxiliary equipment of a trolleybus using energy from recuperation with a traction motor is presented. [ABSTRACT FROM AUTHOR]